[Terrapreta] diatoms and CO2

[Gerald Van Koeverden]

FYI:  Beware of a scam to profit from selling carbon credits via iron  
fertilization of the oceans to promote the growth of diatoms:

Diatoms have previously been studied for their ability to soak up  
carbon dioxide. The cells account for more than 20 per cent of the  
carbon dioxide that is removed from the atmosphere each year, an  
amount comparable to that removed by all the planet's rainforests,  
the researchers said.

http://www.cbc.ca/technology/story/2008/01/21/algae-computers.html

  “Seeding the blue oceans with natural iron dust is a dirt-cheap way  
to revive the plankton, remove megatons of CO2 from the atmosphere,  
reduce global warming, and lower marine acidity.”
Why do we have to add iron to the sea? Because research shows that  
the oceans have an iron deficiency. Dissolved iron is a necessary  
micronutrient for plankton; iron plays a vital role in  
photosynthesis. But iron levels in the seas are perilously low: iron  
content in ocean water is a mere 3 parts per trillion."

"Diatom’s scientists have devised a simple scheme: dump “iron dust” …  
iron-rich dirt found in abundance near deposits of iron ore … into  
the ocean to create large blooms of plankton..."

"When operated on a large scale, the Diatom process can “sequester”  
millions of tonnes of CO2 at about 30 cents per tonne. The current  
market value of a carbon credit is about U.S. $30 per tonne for  
carbon credits allowing Diatom to mark-up its “product” – the carbon  
credits it sells – one hundred fold. That’s a profit margin of 99%."

http://www.bly.com/newsite/Pages/diatom_mailer.pdf

Thus far, iron enrichment experiments have been small and mainly  
intended to determine the role of iron as a limiting nutrient for  
phytoplankton growth in HNLC water. Studies of carbon export have  
been limited, it is difficult to verify sequestration, and we do not  
yet fully understand the fate of biogenic carbon induced from iron  
enrichment.36 Experimental sediment traps deployed during SOFeX  
showed that after nutrient resources were depleted only a small  
fraction of iron-induced organic carbon reached the bottom. Other  
pathways may be available to the carbon, particularly  
remineralization via bacteria and mesozooplankton grazing. 37  
furthermore, just as experiments with sea water in a small bottle may  
not accurately reflect the same processes that occur naturally in an  
ocean, small scale experiments in selected regions may not reflect  
large scale trends that play a role in phenomena such as global warming.

http://www.csa.com/discoveryguides/oceangard/overview.php

"The Cells That Rule the Seas" by biological oceanographer Sallie W.  
Chisholm,

  Scientific American, September 28, 2006

  ...she is equally convinced that large-scale fertilization would be  
a mistake. "How can we manipulate this system when we don't know  
what's in it?" she asks. "The oceans are performing all kinds of  
functions we don't understand." If the approach works at all-- still  
an open question-- it will inevitably alter the food web, promoting  
the growth of larger cells such as diatoms at the expense of smaller  
ones such as Prochlorococcus, with unknown effects rippling through  
the trophic levels.
  By no means an activist, Chisholm rarely joins causes or signs  
petitions, but on this issue she feels obliged to speak out. "I  
didn't spend my life studying how aquatic ecosystems work only to  
have this fundamental knowledge ignored," she says.

Most ocean scientists agree with Chisholm about iron fertilization.  
Nevertheless, she observes, "this idea just won't go away." Every  
year she hears of a different patent filed, a new commercial venture  
or some other fertilization scheme. Part of the problem is the profit  
motive, but Chisholm also holds scientists responsible. Although it  
is essential to clarify iron's role as a limiting nutrient, she says,  
this research is commonly justified by tying it to ocean  
fertilization. "Somehow we must evolve to the point where people  
accept the importance of studying how the biosphere works-- what  
regulates the flow of energy and cycling of elements-- in its own  
right."

http://www.oceanconserve.org/shared/reader/welcome.aspx? 
linkid=61285&keybold=%20carbon%20ocean%20iron%20fertilization


Gerrit
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